This invention relates to controls for hydrostatic transmissions.
Vehicle hydrostatic transmissions typically include a hydraulic pump operating a hydraulic motor which drives the vehicle and a combined direction and speed control for selectively controlling the direction of the fluid flow through the motor, and thus direction of vehicle movement, and for controlling the volume of fluid flowing to the motor, and thus vehicle speed. One type of control mechanism is operated by a pivotally mounted foot pedal which can be rocked in opposite directions to both shift the transmission from neutral to either forward or reverse positions and control vehicle speed.
It is desirable for such a control mechanism to include means for insuring that the transmission is returned to the neutral position when the vehicle is stopped and for positively retaining it in a neutral position in order to prevent creeping. The retention means should be capable of releasing upon the application of a relatively low force on a foot pedal in order to prevent sudden vehicle movement after the transmission has been shifted into a operative position.
Representative prior constructions of hydrostatic transmission controls including means for automatically returning transmission to a neutral position are disclosed in Fatur U.S. Pat. No. 4,086,823, issued May 2, 1978, and Haffner U.S. Pat. No. 3,541,878, issued Nov. 24, 1970. Attention is also directed to Massarotti U.S. Pat. No. 2,703,496, issued Mar. 8, 1955.
Representative prior constructions of foot pedal arrangements including retention means are disclosed in Narcovich U.S. Pat. No. 2,483,224, issued Sept. 27, 1949, Alspaugh U.S. Pat. No. 1,402,131, issued Jan. 3, 1922, and Friddle U.S. Pat. No. 1,321,615 issued Nov. 11, 1919.